The word "her" refers to Jerusalem which is described as if it were a woman. AT: "her inhabitants" or "the people of the city" (See: [[rc://en/ta/man/translate/figs-personification]])
This means they traded their wealth and their valuables in exchange for food. AT: "They have traded their precious treasures in exchange for food" (See: [[rc://en/ta/man/translate/figs-explicit]])